One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10)(11,19)(12,13)(14,17)(15,18)(16,22)(20,23)(21,24)(25,26,29,32)(27,30,34,38)(28,31,36,33)(35,39,40,37)(1,3,4,8)(2,5,6,7)(9,11)(10,16)(12,20)(13,21)(14,23)(15,22)(17,24)(18,19)(25,27,29,34)(26,30,32,38)(28,35,36,40)(31,39,33,37)(3,8)(5,7)(9,12,15,17)(10,13,18,14)(11,20,22,24)(16,21,19,23)(26,31)(27,34)(28,36)(30,37)(32,33)(38,39)(2,6)(5,7)(9,13,15,14)(10,17,18,12)(11,21,22,23)(16,24,19,20)(25,27)(26,30)(28,35)(29,34)(31,39)(32,38)(33,37)(36,40)(9,14,15,13)(10,17,18,12)(11,21,22,23)(16,20,19,24)(26,32)(27,34)(31,33)(35,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.